Letdown valve
Letdown valve
(OP)
Hi there,
I'm wondering if there is any energy loss when steam flows through a let down valve.
Example:
Boiler is producing steam at 11 barg. Pressure drop to the end user is around 1 barg. End user only needs 9 barg so a valve was throttled to reach the pressure.
Is there any energy loss going from high pressure to low pressure?
I'm wondering if there is any energy loss when steam flows through a let down valve.
Example:
Boiler is producing steam at 11 barg. Pressure drop to the end user is around 1 barg. End user only needs 9 barg so a valve was throttled to reach the pressure.
Is there any energy loss going from high pressure to low pressure?





RE: Letdown valve
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: Letdown valve
RE: Letdown valve
RE: Letdown valve
I'm thinking of installing a prv on the line to improve the control of th system
Would it save energy or flow on the line?
RE: Letdown valve
When throttling saturated steam from about 400 PSIA or less, it becomes superheated at the downstream pressure, and at a lower temperature than the initial upstream saturated temperature.
When throttling saturated steam from pressures well above about 400 PSIA, to becomes wet at the downstream pressure, and at a lower temperature than the initial upstream saturated temperature.
RE: Letdown valve
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: Letdown valve
The valve by itself in general won't save you any money since the steam has the same enthalpy.
One exception might be if you have steam turbines that exhaust to the 9 bar header. Lower header pressure = low steam consumption by the turbines. There might be some other cases depending what the steam is used for.
RE: Letdown valve
RE: Letdown valve
Introducing a pressure regulating device would give an advantage of controlling the flow if there is upstream pressure fluctuations right?
RE: Letdown valve
Yes.
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: Letdown valve
RE: Letdown valve
What do you mean here? And what is the relevance to the posted questions?
RE: Letdown valve
"Nobody expects the Spanish Inquisition!"